You could use the future tense, but you can use the present tense to express future events if it's clear that the event is in the future (e.g., by adding "domenica prossima"). The same is true in English: notice it's "I go" not "I will go" above. I'm not sure if this analogy always holds, though.
In English we can use the "Present Continuous" or the " To be going to " future tenses, when referring to the future. We use the Present simple usually with timetables ( when referring to the future ).
The train leaves at 5 on Monday. I go swimming at 7 on Tuesday.
So in my opinion; Next Sunday I go to the zoo. Just sounds a bit odd.
I prefer I am going to the Zoo next Sunday.
Good luck with your studies! ( I know I need it ) In bocca di lupo.
I was going to make the same point about English, though I was going to use a different example:
We would say "Next Sunday I'm going to the zoo" (or "I'm going to the zoo next Sunday"). Clearly, this is a future event, yet we still use the present tense. We could also say "Next Sunday I will go to the zoo", or "Next Sunday I'm going to go to the zoo", but it's less common.
The one thing you wouldn't say in English is "Next Sunday I go to the zoo" which is the supposedly correct answer here. This is a constant problem with Duolingo - one never knows when one has to be ridiculously literal in translating (though usually it's a safe bet). Sometimes you can get away with more accurate translations that actually reflect what one would say in English, but it's a crapshoot. This time, I knew that if I said "Next Sunday I'm going to the zoo" it would be counted wrong, even though it's better than the "right" answer.
I know what you mean, but personally I don't know the difference when people say 'next' sunday, 'this' sunday, or 'sunday week' and English is my first language. Maybe I'm too literal minded, but surely 'next' sunday, means 'this' sunday. It's 'next' because it's the next one that happens, therefore the prossima one! The sooner this 'next' and 'this' separation ends the happier I will be!
I guess 'next sunday' is sometimes short for 'next week's sunday'. Otherwise it doesn't make much sense, does it?
Yes, the SBB trains do say "prossima fermata" :)
I think it's ambiguous. "Domenica prossima" can refer to either the upcoming Sunday or to the Sunday of the next week. If it's Friday or Saturday, "domenica prossima" is more clearly next week; if it's earlier in the week it's less clear. The same confusion exists in (US) English.
Sunday is a bit of a problematic case for discussing this since in the US, Sunday is the first day of the week, while in Europe it's the last day of the week. So, I'll switch to Friday.
As for the ambiguity in English, I just meant that in US English, "next Friday" can mean either the upcoming Friday or the Friday after that. It's more ambiguous the farther from Friday it is, but is usually used to mean the Friday of the following week. "This Friday" is the upcoming Friday. In UK English, "Friday week" is used for the Friday of the next week. I have also heard "Friday next", but I hear it so rarely I'm not actually sure if it means anything different from "next Friday".
Regardless, I think it's best practice just to say "Sunday the 7th" or similar ("domenica il 7") or "Sunday of next week" ("domenica della settimana prossima") when you want to be clear.
I translated the word order too, "Sunday next I go to the zoo." I don't know if it's technically correct, but it's definitely something I've heard people say. Like, "When are you going to the zoo?" "Sunday next." So when this sentence put 'Domenica' before 'prossima' I just... translated it like that.
You would say either "On Sunday" meaning the upcoming Sunday, or "Next Sunday" which could be ambiguous as per the above discussion. However you would not say "On next Sunday" in this context. In this case the "On" and the "next" are alternatives in common speech and you cannot combine them even though one is a preposition and one is an adjective. I am not sure why, but English is full of illogical constructions. It might be that while "On Sunday" is an adverbial phrase qualifying "go", "Next Sunday" is trying to act as an adverbial phrase even though it really is not (at least in the sense that it does not start with a preposition). It just an abbreviation of the adverbial phrase "On next Sunday" - which is never used.